1. Field of the Invention
The present invention relates to working apparatus for performing a predetermined work on a workpiece. More particularly, the present invention pertains to a working apparatus which is adapted for performing a predetermined work
on a workpiece which is being conveyed in a predetermined direction.
2. Description of the Prior Art
Automatic working apparatus are widely used in various
manufacturing plants. For example, in automobile manufacturing plants, welding and assembling robots are used for performing desired works on workpieces such as automobile bodies. Conventionally, the workpieces are carried by a conveyor and cyclically stopped and located in positions at working stations where the robots are positioned.
In order that the works be carried out in an efficient manner, it is preferable that the works be done while the workpieces are being conveyed. Japanese patent application 57-234706 filed on Dec. 27, 1982 and disclosed for public inspection on July 11, 1984 under the disclosure number 59-120381 discloses a working apparatus including a working robot which is mounted on a carriage movable along a workpiece conveyor at a speed substantially the same as the transfer speed of the workpiece on the conveyor. Usually, the workpiece is carried by a workpiece hanger or trolley provided on the conveyor so that the aforementioned Japanese patent application teaches to lock the robot carriage to the hanger or trolley to make the robot move together with the workpiece.
It should however be noted that the arrangement disclosed by the Japanese patent application is not satisfactory because the working robot cannot be accurately located with respect to the workpiece. Generally, workpieces are simply placed on the hangers or trolleys without any locating means so that, even if the robots are accurately located with respect to the hangers or the trolleys, there may be a certain degree of positioning errors between the working robots and the workpieces.